The transmission time is the amount of time from the beginning until the end of a message transmission. In the case of a digital message, it is the time from the first bit until the last bit of a message has left the transmitting node. Source
The packet transmission time in seconds can be obtained from the packet size in bit and the bit rate in bit/s as:
Packet transmission time = Packet size / Bit rate
- Length of packet
- Bandwidth
T1 (Starting Time)
+--------------A B-------+
|01001000100010| | |
+--------------+ +-------+
T2
+--------------A B-------+
| |01001000100010 | |
+--------------+ +-------+
Propagation delay is the time that it takes for a bit to reach from one end of a link to the other. The delay depends on the distance (D) between the sender and the receiver, and the propagation speed (S) of the wave signal. It is calculated as: D/S. Source
The time it takes for the first bit to travel from the sender to the receiver Source
- Depends on propagation speed,where propagation speed depends on physical medium of the link.(in the range of 2 × 10^8 meters/sec for copper wires and 3 × 10^8 for wireless communication)
Propagation time = Distance / propagation speed
Propagation Time is, how long it takes for a bit to reach B from A.
+------A B-------+
|010010|---->--transmission_medium------>---| |
+------+ +-------+
The packet delivery time or latency is the time from when the first bit leaves the transmitter until the last is received. Source
Considering a physical link.
Packet delivery time = Transmission time + Propagation delay
T1 (Starting Time)
+------A B-------+
|010010| | |
+------+ +-------+
T2
+------A B-------+
| |010010 | |
+------+ +-------+
T3(Ending time)
+------A B-------+
| | |010010 |
+------+ +-------+
T2 - T1 = Transmission time
T3 - T2 = Propagation delay
T3 - T1 = Packet delivery time
Therefore, Packet delivery time = Transmission time + Propagation delay
The round-trip time or ping time is the time from the start of the transmission from the sending node until a response (for example an ACK packet or ping ICMP response) is received at the same node. It is affected by packet delivery time as well as the data processing delay Source
Roundtrip time = 2 × Packet delivery time + processing delay
In case of only one physical link, the above expression corresponds to:
Link roundtrip time = 2 × packet transmission time + 2 × propagation delay + processing delay
If the response packet is very short, the link roundtrip time can be expressed as close to:
Link roundtrip time ≈ packet transmission time + 2 × propagation delay + processing delay
In theory, we will assume, there is no processing delay, the Round Trip Time = 2 * Propagation Delay.
- https://ieeexplore.ieee.org/abstract/document/6705357
- https://ieeexplore.ieee.org/abstract/document/8319486
- https://ieeexplore.ieee.org/abstract/document/6705357
- https://www.imperva.com/learn/performance/round-trip-time-rtt/
- No reference found, regading the multiplication of lenght of packet by 1-bit round trip time
Note: Transmission of frames, packet or anything, with respect to physical layer, it converts them to electrical pulses, which represent binary data.
T1 (Starting Time)
+------A B-------+
|010010| | |
+------+ +-------+
T2
+------A B-------+
| |010010 | |
+------+ +-------+
T3(Ending time)
+------A B-------+
| | |010010 |
+------+ +-------+
T2 - T1 = Transmission time
T3 - T2 = Propagation delay
T3 - T1 = Packet delivery time
Therefore, Packet delivery time = Transmission time + Propagation delay
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent